1 // SPDX-License-Identifier: GPL-2.0
2 
3 /*
4  * Intel PMC Core platform init
5  * Copyright (c) 2019, Google Inc.
6  * Author - Rajat Jain
7  *
8  * This code instantiates platform devices for intel_pmc_core driver, only
9  * on supported platforms that may not have the ACPI devices in the ACPI tables.
10  * No new platforms should be added here, because we expect that new platforms
11  * should all have the ACPI device, which is the preferred way of enumeration.
12  */
13 
14 #include <linux/acpi.h>
15 #include <linux/module.h>
16 #include <linux/platform_device.h>
17 
18 #include <asm/cpu_device_id.h>
19 #include <asm/intel-family.h>
20 
21 #include <xen/xen.h>
22 
intel_pmc_core_release(struct device * dev)23 static void intel_pmc_core_release(struct device *dev)
24 {
25 	kfree(dev);
26 }
27 
28 static struct platform_device *pmc_core_device;
29 
30 /*
31  * intel_pmc_core_platform_ids is the list of platforms where we want to
32  * instantiate the platform_device if not already instantiated. This is
33  * different than intel_pmc_core_ids in intel_pmc_core.c which is the
34  * list of platforms that the driver supports for pmc_core device. The
35  * other list may grow, but this list should not.
36  */
37 static const struct x86_cpu_id intel_pmc_core_platform_ids[] = {
38 	X86_MATCH_INTEL_FAM6_MODEL(SKYLAKE_L,		&pmc_core_device),
39 	X86_MATCH_INTEL_FAM6_MODEL(SKYLAKE,		&pmc_core_device),
40 	X86_MATCH_INTEL_FAM6_MODEL(KABYLAKE_L,		&pmc_core_device),
41 	X86_MATCH_INTEL_FAM6_MODEL(KABYLAKE,		&pmc_core_device),
42 	X86_MATCH_INTEL_FAM6_MODEL(CANNONLAKE_L,	&pmc_core_device),
43 	X86_MATCH_INTEL_FAM6_MODEL(ICELAKE_L,		&pmc_core_device),
44 	X86_MATCH_INTEL_FAM6_MODEL(COMETLAKE,		&pmc_core_device),
45 	X86_MATCH_INTEL_FAM6_MODEL(COMETLAKE_L,		&pmc_core_device),
46 	{}
47 };
48 MODULE_DEVICE_TABLE(x86cpu, intel_pmc_core_platform_ids);
49 
pmc_core_platform_init(void)50 static int __init pmc_core_platform_init(void)
51 {
52 	int retval;
53 
54 	/* Skip creating the platform device if ACPI already has a device */
55 	if (acpi_dev_present("INT33A1", NULL, -1))
56 		return -ENODEV;
57 
58 	/*
59 	 * Skip forcefully attaching the device for VMs. Make an exception for
60 	 * Xen dom0, which does have full hardware access.
61 	 */
62 	if (cpu_feature_enabled(X86_FEATURE_HYPERVISOR) && !xen_initial_domain())
63 		return -ENODEV;
64 
65 	if (!x86_match_cpu(intel_pmc_core_platform_ids))
66 		return -ENODEV;
67 
68 	pmc_core_device = kzalloc(sizeof(*pmc_core_device), GFP_KERNEL);
69 	if (!pmc_core_device)
70 		return -ENOMEM;
71 
72 	pmc_core_device->name = "intel_pmc_core";
73 	pmc_core_device->dev.release = intel_pmc_core_release;
74 
75 	retval = platform_device_register(pmc_core_device);
76 	if (retval)
77 		platform_device_put(pmc_core_device);
78 
79 	return retval;
80 }
81 
pmc_core_platform_exit(void)82 static void __exit pmc_core_platform_exit(void)
83 {
84 	platform_device_unregister(pmc_core_device);
85 }
86 
87 module_init(pmc_core_platform_init);
88 module_exit(pmc_core_platform_exit);
89 MODULE_LICENSE("GPL v2");
90